The present invention generally relates to miniature optically transparent windows.
Many MEMS structures require that light be shines into and through them. One example of such a device is a chip-scale atomic clock as described in U.S. Pat. No. 6,900,702. Recent trends have emphasized ultra compact, high performance architectures such as these MEMS based devices, which often utilize semiconductor fabrication techniques to form miniaturized components on the surface of a wafer. However, semiconductor fabrication techniques are often limited in forming some MEMS structures, such as miniature windows that are transparent in the horizontal direction (e.g. a direction parallel to the surface of the wafer). In some cases, horizontally transparent windows have been fabricated by bonding a transparent structure, as a Pyrex™ glass structure, onto a top and/or bottom surface of a MEMS wafer. While these devices can operate satisfactory, fabrication improvements are desired.